Israeli officials are tight-lipped as negotiators hammer out details in Cairo to free Israeli soldier Gilad Shalit, being held by Hamas, in exchange for hundreds of Palestinian prisoners.

The Israeli soldier, captured by Hamas in 2006, is seen in a video released… (Associated Press )

Reporting from Jerusalem — Expectations of a swap of hundreds of jailed Palestinian militants for an Israeli soldier held by Hamas soared Monday after some of the most promising signs of progress in years of negotiations.

Citing the sensitivity of indirect talks with its bitter enemy, the Israeli government imposed silence on its officials and unusually tight censorship on news media to try to keep the details of an emerging agreement under wraps.

Israeli Prime Minister Benjamin Netanyahu and the Hamas leadership in the Gaza Strip played down the likelihood of an imminent deal, even as other officials on both sides fueled speculation of one.

"The light has dawned," Ahmad Bahar, a Hamas official who is deputy speaker of the Palestinian parliament, declared to a group of relatives of Palestinian prisoners. "You will soon meet your imprisoned sons."

Negotiations have been underway since shortly after Sgt. Gilad Shalit was captured from a border post and brought into Gaza in June 2006, but conditions for a deal have ripened only recently. Early last month Israel freed 20 Palestinian women in return for a proof-of-life video of the 23-year-old tank crewman.

Talk of Shalit's impending release began filling Israeli and Palestinian news media and blogs over the weekend, fueled by unofficial reports of concessions by both sides.

Israeli President Shimon Peres, after meeting in Cairo with Egyptian and German mediators Sunday, confirmed there had been progress in the negotiations.

Mousa abu Marzouk, Hamas' deputy political leader, also reported a narrowing of differences over terms of a swap as senior Hamas officials from Gaza and Syria arrived Monday in Cairo to meet with the mediators.

Neither Peres nor Abu Marzouk would elaborate publicly.

But several unofficial accounts said Shalit would be sent to Egypt in return for about 450 Palestinian prisoners, then brought home to Israel in exchange for hundreds more.

One account, by the Hamas journal Risala, said the two sides had agreed on all but one of the prisoners to be included in the swap. A Hamas official in Cairo said, however, that Hamas was still discussing an Israeli proposal that 150 of the Palestinians to be freed should be expelled to other countries and barred from returning to Gaza or the West Bank.

Some Hamas officials said they hoped an agreement would be concluded by Friday, the start of the Muslim holiday of Eid al-Adha.

On Monday evening, however, Hamas' leadership issued a statement saying "it is still too early to talk about definitive results any time soon." It accused Israel of leaking details of the talks to raise the expectations of prisoners' families and bring pressure on Hamas negotiators to make concessions.

Netanyahu resisted pressure to explain the reported terms to members of his right-wing Likud Party. An Israeli official who spoke on condition of anonymity after the closed meeting said Netanyahu told them "there is no deal and no decision. . . . It is still not clear what is happening with the other side."

The Israeli leader said any deal would go to the Knesset, Israel's parliament, for debate and to the Cabinet for approval.

During decades of conflict, Israel has made several lopsided deals with Arab adversaries to trade large numbers of prisoners for a few captured soldiers, or the remains of dead soldiers. Some of those exchanges came under criticism in Israel after freed prisoners returned to militant activity against the Jewish state.

Some Israelis now complain that the government is stifling debate about the central issue of any negotiation with Hamas: how far Israel should yield to an Islamic group that calls for further hostage-taking and advocates its destruction.

Three Israelis whose children were killed years ago in a militant attack on a bus said they were preparing a Supreme Court petition to force disclosure of the names of those prisoners Israel is prepared to set free. Some believed to be on the list have been convicted of planning or carrying out deadly attacks.

"People don't know who will be released," said Ron Kerman, whose 17-year-old daughter was killed in a suicide bombing six years ago. "When the public learns what we're talking about, the blank check we're giving the government will become much, much smaller."

Col. Sima Vaknin-Gil, the chief military censor, defended the clampdown in an interview with Israel Radio, saying it was meant to facilitate negotiations, not limit debate.

On the same program, Intelligence Affairs Minister Dan Meridor said: "Those who don't know can talk. Those who know should keep silent."